1) Repetitive segments of DNA two to five nucleotides in length (dinucleotide/trinucleotide/tetranucleotide repeats), scattered throughout the genome in the non-coding regions between genes or within genes (introns), often used as markers for linkage analysis because of high variability in repeat number between individuals. These regions are inherently unstable and susceptible to mutations.

2) Microsatellite sequences are repetitive DNA sequences usually several base pairs in length. Microsatellite sequences are composed of non-coding DNA and are not parts of genes. They are used as genetic markers to follow the inheritance of genes in families.

3) Any of numerous short segments of DNA that are distributed throughout the genome, that consist of repeated sequences of usually two to five nucleotides, and that are often useful markers in studies of genetic linkage because they tend to vary from one individual to another.